<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        article{
            width: 500px;
            height: 300px;
            background-color: #ccc;
            margin:0 auto;
        }
        div{
            width: 100px;
            height: 100px;
            background-color: red;
            margin:10px;
            float:left;
        }
        p{
            width:100px ;
            height: 100px;
            background-color: orange;
        }
        section::after{
            content: "";
            clear: left;
            display: block;
        }
        /* h1{
            clear: left;
        } */
    </style>
</head>
<body>

    <article>
        <section>
            <div>div1</div>
            <div>div2</div>
            <div>div3</div>
        </section>
        <!-- <h1></h1> -->
        <p>p1</p>
        <p>p2</p>
        <p>p3</p>
    </article>
</body>
</html>